Peek the Geek

How taut should my chain be on my singlespeed (I'm using a dedicated ss frame w/ track-style dropouts)? With a little sag it seems to run fine. If I tighten it up, though, there's a small amount of noise and resistance due to the chainline not being perfect.

Do I keep running a little slack in the chain? Or is there a way to improve my chainline?

mcoine

What kind of cranks and bb do you have? An adjustable (side to side) bb would be a good thing to have. post a picture.

Jameson

Mine has some sag, looking at the chain it appears 98% straight but if you pinch the top and bottom chains together there is about 1/2 inch of sag. I hope that makes sense. I've had some trouble with excess sag, usually with multi speed chains. I now have an Acuchain Kool Freestyle chain with niffty hollow pins, no sag issues.

Peek the Geek

Cranks are Bontrager Race Lite SS (which I believe are just rebadged Truvativ Stylo SS). BB is a Race Face Evolve ISIS, 73/68mm. BB shell is 68mm, so I am using the recommended 2.5mm spacer on the drive side. Is an adjustable BB the only way to improve my chainline? What type of ISIS adjustable BBs are out there?

Here's a pic:

Dannihilator

You need a little more tension.

mcoine

whats the hub?

Peek the Geek

Yep, I know it, but I'm running into chain line issues when the chain is under more tension, as mentioned above.

Peek the Geek

Hub is a Paul WORD. I'm currently using an ACS Claw freewheel, if that matters at all.

a2psyklnut

First of all, I agree your chain is too loose.

When you backpedal, do you get a tight spot and then a loose spot? That usually occurs if the front chainring isn't perfectly centered.

An old trick is to loosen the chainring bolts a teensy bit, then line up the cranks at the tight spot and then use a rubber mallet and tap the leading edge of the front chainring to help center it. Do this a couple of times until the tight/sloppy is evened out.

Another trick is to tighten wheel cocked over to where the tire hits the chainstay on the drive side, the chain is tight and you tighten the drive side axle nut. Then you straighten the wheel and tighten down the non-drive side.

Also, although very durable ACS freewheels are built with hideously bad tolerances. A tight/loose condition is most likely accentuated by the freewheel.

The only thing to solve that problem is to plunk down $100 for a White Bros.

mx_599

you're sort of in the same boat as me with 73mm bb in 68mm shell. how bad is chain line do you estimate. if it is not too bad, it would seem to me that you could go in either direction a couple millimeters with spacers.

Peek the Geek

Thanks for the reply. The issue isn't an off-center ring, though (at least not at this point), and I have no problem getting the chain as tight as it should be.

The problem seems to be that the chainline is too far off. The rear chainline measurement is about 3-4mm outside the front chainline measurement---enough so that, when taut, the chain travels onto the cog and front ring at such an angle that there is significant resistance/rubbing.

So what I would have to do is somehow move the rear cog inward or move the front chainring outward a few mm.

As for the quality of the ACS freewheel, I just built this bike up and had never ridden singlespeed before, so I wanted to try a couple different gearing combinations to see what I prefer. ACS was a cheaper way to do that than an ENO, but I'll be making the upgrade eventually.

rocky_rider

Why is it so bad to have to much sag in your chain? Can it do damage?

mcoine

Is the chainring bolted to the spider?.. bolt the chainring on the outside of the spider and get rid of the guard.